The objective of the present research project is to investigate the actions of renal prostaglandins (PG) on the tubular and vascular functions of the kidney using recollection micropuncture, tubular and vascular functions of the kidney using recollection micropuncture, tubular microinjection, clearance and servo nulling micro pressure recording techniques. Indomethacin and meclofenamate (inhibitors of PG synthesis), and arachidonic acid (AA, precursor and stimulator of PG synthesis) will be utilized to elevate and reduce intrarenal PG concentration and identify functions affected by PG. Changes in PG metabolism in rats (synthesis and degradation) will be evaluated in vivo and in vitro during stimulation and inhibition of PG synthesis. The effect of an antihypertensive drug, clonidine, on renal tubular and vascular function and on the renal kallikrein-kinin and PG systems will also be studied along with the interactions between the diuretic action of furosemide and PG metabolism. The direct tubular action of bradykinin from the luminal side on sodium transport will be evaluated. The results of the proposed work will facilitate our understanding of the role the kidneys play in the regulation of systemic BP and hypertension and how intrarenal autacoids modulate these functions.